Boiler



March 8, 1966 1. PHILLIPS BOILER Filed Jan. 27, 1964 United States Patent O 3,238,928 BOILER James L. Phillips, 2635 S. Avers Ave., Chicago 23, Ill.

Filed Jan. 27, 1964, Ser. N0. 340,337

2 Claims. (Cl. 122-149) This invention relates to heating devices and more particularly to a new and improved boiler.

Com-mon boiler -construction utilizes an enclosed boiler shell -for holding a quantity of water to ybe heated. Within ythe shell is a large heating chamber of re drum and a plurality of smaller heat tubes. The heat tubes extend longitudinally of the shell andare secured at either end lbetween upright tube sheets which enclose the ends of the boiler shell. The combustion chamber or re drum also extends longitudinally of the shell and is similarly secured to the tube sheets. Suitable means are provided `for circulating the heated air :from the combustion chamber through the heat tubes to heat the water in the shell. Since combustion takes place in the lire drum, greater temperatures exist within the lire drum. Thus the lire drum expands at a rate disproportionate to that o-f the heat Vtubes and because both the lire drum and heat tubes are locked at either end to the tube sheets this unequal expansion yfrequently results in cracking of the tube sheets, resulting in costly and time consuming repairs.

It is lfurther common in -boiler construction to secure the lfront and rear heads or end plates to the tube sheets by a multitude of bolts. Thus a great deal of time spent in attempting to repair or service a boiler is spent in merely attempting to gain access to the interior of the boiler.

`It is therefore a general object of this invention to provide a new and improved boiler.

It is a primary object of this invention to provide a new and improved boiler wherein expansion of the re drum relative to the re tubes will not result in damage to the boiler.

It is another object of this invention to provide a new and improved boiler which will permit the fire drum to expand relative to the heat tubes without fracturing the tube sheets.

A further object of this invention is to provide a new and improved boiler having a reduced diameter portion on the fire drum between the tube sheets which will permit the fire drum to expand relative to the heat tubes and tube sheets.

Yet another object of this invention is to provide a new and improved boiler constructed to permit easy access to the interior of the boiler for servicing and repair.

It is still another object o-f this invention to -provide a new and i-mproved boiler wherein the rear boiler .head covering the rear tu-be sheet and defining a heat circulation chamber is Secured to the boiler by only a hinge, permitting the rear head member to freely swing open in response to sudden excessive pressures within the re drum as well as facilitating easy access to the interior of the boiler.

Further objects and advantages will become apparent `from the following detailed description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a fragmentary longitudinal section view, partially shown in side elevation, of the boiler of this invention; and

FIGURE 2 is a vertical section view taken along the line 2--2 of FIGURE 1.

While this invention `is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail an embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplilication of the prinice ciples of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

Referring now to the drawings, in FIGURE 1 there is shown the boiler 10 of this invention. The boiler is provided with a suitable burner 12 for heating the water 14 within the boiler. The boiler c-omprises a substantially tubular 'boiler shell 16 which is enclosed at either end by the 'front and Vrear disc-like upright tube sheets 18 and 20, respectively, to form a water jacket for containing the water.

The front sheet is enclosed in the area of the re tubes by the front end plate or head 22. The front end plate 22 is secured to the -front tube sheet 18 by only two bolts 23, which are threaded on the nuts 23a which project outwardly from the -front tube sheet.

The rear end plates 24 encloses the rear tube sheet and is secured to the boiler by only a single hinge 24a which permits the rear end plate to freely swing open in response to excessive pressures in the interior of the -boiler as well as permitting rapid and easy access to the Iboiler interior for servicing or the like.

The burner is in communication with the interior o-f the Iboiler shell by means of a tubular fire tube 25 which communicates with the interior of a larger diameter combustion chamber or iire drum 26, positioned in the interior of the boiler shell between the tube sheets, wherein the cornbustion takes place to provide the hot air for heating the water in the boiler shell. The rear end plate 24 has a segmental spherical configuration defining a closed charnber 27 and is lined with a suitable refractory 27a to direct the heated air (as indicated by the arrows) -from the fire drum through the heat tubes 28. As the heated air passes through the heat tubes 28, the water surrounding the tubes is heated in the conventional fashion. The heated air exhausts through the `front tu-be sheet by way of an exhaust bonnet 29 at the top of the front end plate 22 and is directed to` atmosphere through an exhaust ilue 30.

In the boiler of this invention, the re drum 26 is substantial-ly a tubular structure with a cylindrical shell 32, which is secured at its open end 32a to the rear tube sheet. The front end of the shell 32 is enclosed with a flat disclike front lire drum wall 33 spaced inwardly lfrom the front tube sheet 18. The re drum wall 33 has a small opening 33a therein to which the re tube 25 is secured. As the iire drum is heated, due to the combustion occuring therein, the drum will attain temperatures higher than those existing in the lire tubes 28 or the boiler shell 16. This will cause the drum to expand at a rate disproportionate to the heat tubes and the boiler shell. In previously known Iboilers wherein both ends of the tire drum, the boiler shell and the heat tubes were held at either end to the tube sheets, this uneven expansion would result in cracking of the tube sheets. With the boiler construction of this invention, as the re drum expands relative to the fire tubes, the fire drum may flex about the perimeter of attachment 34 between the fire tube and the `front iire drum wall. This will permit the lire drum to -expand relative to the lire tubes, the boiler shell and the tube sheets without exerting stresses on the tube sheets. Thus, the relative expansion of the re drum may be accommodated without causing or tending to cause tube sheet cracking.

It should Ibe noted that the expansion joint of this invention could be provided at the opposite end of the boiler or could be provided at a point intermediate the ends of the fire drum. In the latter construction, both the front and rear ends of the fire drum could have an opening of a size commensurate with the opening 32a whereas the center of the fire drum would Ibe provided with a reduced diameter portion about which the fire drum could flex in response to expansion caused by the excessive heat therein. While in the preferred embodiment of my invention I prefer to form the expansion joint at a point spaced inwardly from the front tube sheet of the boiler, it is to -be noted that the novelty of 'my invention resides in providing such an expansion joint in the re drum at a point -between the tube sheets to accommodate the re drum expansion.

The boiler may be provided with suitable supply and drain means, such as a water inlet 37 and a water drain 38, suitable control devices, such as a thermostat device 39, may also be provided for actuating suitable control means in response to boiler temperatures.

The boiler of this invention utilizes a simple construction which promotes the economy of production of the boiler. The expansion joint itself, which eliminates the common reoccuring problem of tube sheet cracking with a simple structural feature of the boiler which, while overcoming a troublesome problem in the prior art, does not add signicantly to the cost of manufacture of the boiler. In addition, the provision of the hinged rear end plate not only adds a safety feature to the boiler by permitting the end plate to swing open in response to sudden blast in the combustion chamber, but also permits ready access to the `interior of the yboiler `for servicing and maintenance. Similarly, the securement of the 4front end plate to the front tube sheet with but two bolts threaded on two nuts also permits rapid and easy access vto the interior of the front portion of the boiler.

I claim:

1. A horizontal re tube boiler, comprising: a generally circular cylindrical 4boiler shell; upright -front and rear tube sheets mounted at each end of said shell; a plurality of heat tubes in said shell, each tube secured at each end to one of said tube sheets; an upright dished end plate over the exterior of said rear tube sheet to dene a closed chamber for the circulation of a heating medium through in said shell secured at one end to said rear tube sheet,

said combustion chamber having an enlarged opening at the one end communicating with the closed chamber defined by said end plate anda 'front wall with a reduced opening at the other end; and a reduced diameter combustion tube secured to the front wall of said combustion chamber in communication with sai-d opening and the interior of said chamber, said combustion tube secured to said front tube sheet and having combustion means mounted thereon to supply said combustion chamber, so that as the heat in said combustion chamber causes the chamber to expand at a rate disproportionate tothe expansion of said heat tubes, the combustion chamber may flex about the point of juncture between said com- Ibustion chamber front wall and said combustion tube to permit said chamber to expand relative to said heat tubes and said tube sheets to prevent cracking of said tube sheets. v

2. The boiler of claim 1 wherein the end plate coverfing the rear tube sheet is only hinged to the yboiler shell to permit the end plate to swing to an open position in response to sudden excessive pressures in said combustion chamber.

References Cited by the Examiner FREDERICK L. MATTESON, I R., Primary Examiner.

KENNETH W. SPRAGUE, PERCY L. PATRICK, f Examiners. 

1. A HORIZONTAL FIRE TUBE BOILER, COMPRISING: A GENERALLY CIRCULAR CYLINDRICAL BOILER SHELL; UPRIGHT FRONT AND REAR TUBE SHEETS MOUNTED AT EACH END OF SAID SHELL; A PLURALITY OF HEAT TUBES IN SAID SHELL, EACH TUBE SECURED AT EACH END TO ONE OF SAID TUBE SHEETS; AN UPRIGHT DISHED END PLATE OVER THE EXTERIOR OF SAID REAR TUBE SHEET TO DEFINE A CLOSED CHAMBER FOR THE CIRCULATION OF A HEATING MEDIUM THROUGH THE HEAT TUBES; AN ENLARGED DIAMETER COMBUSTION CHAMBER IN SAID SHELL SECURED AT ONE END TO SAID REAR TUBE SHEET, SAID COMBUSTION CHAMBER HAVING AN ENLARGED OPENING AT THE ONE END COMMUNICATING WITH THE CLOSED CHAMBER DEFINED BY SAID END PLATE AND FRONT WALL WITH A REDUCED OPENING AT THE OTHER END; AND A REDUCED DIAMETER COMBUSTION TUBE SECURED TO THE FRONT WALL OF SAID COMBUSTION CHAMBER IN COMMUNICATION WITH SAID OPENING AND THE INTERIOR OF SAID CHAMBER, SAID COMBUSTION TUBE SECURED TO SAID FRONT TUBE SHEET AND HAVING COMBUSTION MEANS MOUNTED THEREON TO SUPPLY SAID COMBUSTION CHAMBER CAUSES THE THAT AS THE HEAT IN SAID COMBUSTION CHAMBER CAUSES THE CHAMBER TO EXPAND AT A RATE DISPROPORTIONATE TO THE EXPANSION OF SAID HEAT TUBES, THE COMBUSTION CHAMER MAY FLEX ABOUT THE POINT OF JUNCTURE BETWEEN SAID COMBUSTION CHAMBER FRONT WALL AND SAID COMBUSTION TUBE TO PERMIT SAID CHAMBER TO EXPAND RELATIVE TO SAID HEAT TUBES AND SAID TUBE SHEETS TO PREVENT CRACKING OF SAID TUBE SHEETS. 